The present invention relates to a suction control unit in a plate suction and lifting device, which sucks and lifts a plate etc. with holes that are processed by a punch press etc. in carrying.
A punch press machine makes holes in a material plate and cuts the plate into a plurality of product plates having holes in it. Though holes are not always made, a plurality of the product plates having holes in it is generally made from a large-sized material plate. Each material plate processed like this is lifted by the plate suction and lifting device such as a loader that is equipped with a vacuum suction pad and is carried to the next process.
A vacuum suction pad sometimes fails to lift a plate, as the suction pressure cannot be increased when a part of the pad is located on a hole in sucking the product plate. When using what is termed a multi-pad composed by a plurality of the micro pads as the vacuum suction pad, the product plate may be lifted up as other micro pad sucks the plate even if a part of the micro pad is located on a hole position. However, even in the case, there is a limit according to the hole size etc.
It is also considered that the pad sucks the product plate other than the holes after the hole position of the product plate is taught to the plate suction and lifting device in advance, but it is difficult to teach the respective hole positions of the product plates regularly and it is not easy to secure the reliability of the teaching data.
It is an object of the present invention to solve the aforementioned problem and to provide a suction control unit in a plate suction and lifting device that can suck and lift a plate having a process hole or a corrugated plate by finding a suckable flat part.
The summary of the present invention will be described with reference to FIG. 1 corresponding to the preferred embodiment. A suction control unit 1 in this plate suction and lifting device controls the suction of a lifting device 2 of a plate W2 by sucking the flat part of the plate W2 by using a suction pad 4, and has a suction pressure detecting means 19 for detecting the suction pressure of the suction pad 4 and a retry control unit 29. If the suction pressure of the suction pressure detecting means 19 does not reach the set pressure when sucking the plate W2, the retry control unit 29 changes the flat part of the plate W2 for being sucked by the suction pad 4 and controls the plate lifting device 2 in order to suck again.
According to this arrangement, if the suction pressure of the suction pad 4 detected by the suction pressure detecting means 19 does not reach the set pressure such that there is the process hole in the position of the plate W2 sucked by the suction pad 4, the retry control unit 29 changes the suction position of the suction pad 4 and sucks the plate again. So, the suction pad 4 can suck the plate with process holes or the corrugated plate by choosing the other flat part and the error of sucking and lifting the plate W2 can be reduced to the utmost.
According to the present invention, the plate suction and lifting device 2 is equipped with a travel body 5 traveling to at least one direction X-direction along the flat direction of the plate W2 between a table 9 for placing the plate W2 and a next process plate discharging part B for placing the plate W2 discharged from this table 9, and this travel body 5 may have the suction pad 4. In this case, the retry control unit 29 can change the flat part of the sucking plate W2 by moving the travel body 4.
If arranged like this, the positions of a plurality of the suction pads are changed in one time unlike the device for moving the suction pad 4 to the travel body 5, so that the arrangement becomes simpler.
Moreover, the travel body 5 can be moved to any direction along the flat direction of the plate W2.
If arranged like this, the position for sucking the suction pad 4 to the plate W2 can be changed easily to either direction, X direction or Y direction.